Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 2 2 2010 06 15 85 88 EN H Ahmadi Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. S Malekian Department of Microbiology, Islamic Azad University, Zanjan Branch, Iran. B Tabaraie Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. D Norouzian Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. F Poormirza-gholi Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. M Nejati Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. MH Hedayati Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. MR Beik Mohammadi Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. A Behnoodi Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. M Izadpanahi Department of bacterial Vaccines and Antigen Production, Pasteur Institute of Iran,Tehran, Iran. 2015 10 01 Background and Objectives: 300 Pseudomonas aeruginosa strains were isolated from hospitalized patients in Iran. Using international antigenic typing system (IATS) antibodies, all strains were classified into 16 serotypes while serotype 14 was not identified among the 17 known serotypes. To evaluate the rate of cross-reactivity between O- antigenic determinants, monospecific polyclonal antibodies were made against whole-killed-cells and live cells of each serotype. Material and Methods: Each antiserum was challenged against homologous and heterologous antigens using slide agglutination test. The degree of agglutination reaction is shown by -ve, 1+ve, 2+ve, 3+ve and 4ve for 0, 25%, 50%, 75% and 100% agglutination respectively. Then, the results were tabulated for further study. Results: The rate of cross-reactivity between O-antigenic determinants demonstrated that strains 10.55 and 15.14 had the highest agglutination reaction with serum of all the homologous and heterologous serotypes. Conclusion: Evaluation of the results obtained from the present study can be applied in production of reliable vaccines and antisera as therapeutic agents or as diagnostic kits. https://ijm.tums.ac.ir/index.php/ijm/article/view/52 https://ijm.tums.ac.ir/index.php/ijm/article/download/52/52